Hydrodynamical :: Hydrodynamical (a.) Pertaining to, or derived from, the dynamical action of water of a liquid; of or pertaining to water power..
Hydrodynamics :: Hydrodynamics (n.) That branch of the science of mechanics which relates to fluids, or, as usually limited, which treats of the laws of motion and action of nonelastic fluids, whether as investigated mathematically, or by observation and experiment; the principles of dynamics, as applied to water and other fluids..
Hydrodynamometer :: Hydrodynamometer (n.) An instrument to measure the velocity of a liquid current by the force of its impact.